The invention relates generally to food cutting systems in which food pieces are suspended in flowing liquid, and more particularly to apparatuses used to divert the food pieces and liquid to one or more destinations.
Many food products, particularly vegetables and fruits, are processed prior to sale to preserve the food so it is safe and appealing at the time of consumption. Furthermore, unless they are in an edible size before processing, food products are sliced or otherwise shaped into an edible size during processing and prior to the preservation process, which can be canning or freezing, among others. Food product slicing is accomplished traditionally with sharpened blades. Such blades can be hand-held, but hand-held knives are relatively slow and dangerous to the person using them. Food cutting machines increase the rate and consistency of slicing, and provide a higher degree of safety in the food slicing industry. Machines have been developed for cutting food products at high speed by propelling them into a stationary or machine-driven blade.
Recent advances in food product cutting technologies have resulted in a hydraulically fed cutting apparatus. The driving force used in this system is moving water, and thus the process is called “hydraulic cutting”, which is referred to by the shorthand term “hydrocutting”. Hydrocutting involves the propulsion of water and food products, typically at very high speed, through a path that includes a stationary cutting blade. In the vegetable and fruit cutting industry, food products are sliced along the longitudinal axis (e.g., French fries) and along the transverse axis (e.g., potato chips). Production cutting systems and related knife fixtures are generally well known in the art of hydrocutting vegetable products. Typical hydrocutting systems have a stationary knife fixture that is mounted at a position along the path of the food product to slice parallel to the flow of water. Such parallel cutters usually cut or slice into strips or, with added motions, into a helical shape. In such a system, the food products are conveyed one-at-a-time in single file succession into the stationary cutting blades with enough kinetic energy to carry the product through the stationary knife fixture.
Hydraulic food cutters are used to cut a wide variety of food products, including potatoes, carrots, beets, zucchini, cucumbers, and others. Cutting potatoes has been the most common application of hydrocutting machines, but it should be understood that hydraulic food cutters are capable of cutting, and are used to cut, a wide variety of food products.
The basic configuration of a conventional hydrocutting system is shown, in schematic format, in FIG. 1. In a typical hydraulic cutting apparatus where potatoes are to be cut, the potatoes are dropped into a tank 10 filled with water and then pumped through conduit into an alignment chute or accelerating tube 14 wherein the potatoes are aligned and accelerated to high speed before impinging upon a fixed array of cutter blades where the potato is cut into a plurality of smaller pieces.
Peeled or unpeeled potatoes are dropped into the receiving tank 10 and a food pump 12, typically a single impeller centrifugal pump, is provided to drive the water and potatoes through the system. The pump draws water from the receiving tank and pumps the water and the suspended potatoes from the tank into the accelerator tube 14, which functions as the converging portion of a venturi. The accelerator tube 14 is used to accelerate, singulate, and align the potatoes immediately prior to impinging upon the stationary knife blades of the cutter blade assembly 16.
As noted above, the water and the food product are pumped through a decreasing diameter accelerating section conduit in order to increase the speed of the food products and water as they approach the blade. Unless otherwise specified, the term “acceleration” and its derivatives are used herein to denote both positive and negative (increasing and decreasing) changes of velocity per unit time. The water and food products increase in speed, orient, and align as they pass through the accelerating section. The accelerating section also singulates the food products, meaning the food products travelling through conduit laterally beside one another are arranged in a “single file” line before each item passes through the cutter head. In FIG. 1, the cutter head is in the cutter blade assembly 16, and is removable for service, change of cutting pattern and/or replacement.
The accelerator tube performs at least three functions. First, the accelerator tube accelerates the water and food product to the velocity required for the combination to pass cleanly and completely through the knife blade assembly. In the case of potatoes, a common velocity range is from about 40 to about 60 feet per second. Second, the accelerator tube aligns and centers each of the food products prior to impingement upon the knife blade assembly. Third, the acceleration of the product causes laterally-aligned products to separate and align longitudinally, thereby entering the cutter in a “single file” line.
Potatoes can be cut into French fry sticks as one example of the use of hydrocutting systems, and this will be used as an example hereafter. A person of ordinary skill will understand, after reading the description herein, how to adapt the apparatus described herein to other food products. Each whole potato impinging upon the knife blade assembly at high speed passes through the cutting blade array and is thereby cut into a plurality of food pieces, for example French fry pieces. The cross section of each of the food strips is determined by the arrangement of the cutter head knives.
A portion of the hydrocutting system separates the food product strips from the water once the strips are past the cutter head. It is desirable to slow down the water column and the food product strips in a controlled manner before this separation portion is encountered. This is because the strips may be fragile (depending on the food product) and gentle handling in the sections following cutting prevents breakage of, or stress on, the strips that would render the strips less desirable. The food strips thus pass with the water into the second half of the venturi which is a diverging tube 18 in which the water and the cut food pieces are decelerated back to a slower velocity. The water and cut food pieces are then deposited onto a dewatering conveyer 20. The water passes through the dewatering conveyor and is collected and recycled back to the receiving tank via a water return line 22. The cut food pieces remain on the conveyor 20 and are carried off for further processing. U.S. Pat. Nos. 5,568,755, 5,806,397, and 4,614,141 are hereby incorporated by reference.
In hydrocutting systems, fruits, vegetables, and other foods, all of which are referred to as “product” in the industry, are suspended in a water solution and the combination is conveyed from source point X to destination point Y through a water-conveying pipe, typically by a vane pump. The product and water are pumped directly through the vane pump and the pipe with little damage. In such processing systems it can be necessary to divert product from its original destination Y to a new destination Z in the pipe network. For example, in the prior art system of FIG. 1, if the product is at source point X, which may be the receiving tank 10, and it is preferred to convey the product to destination point Z, which may be a cutter blade assembly in a different tube, instead of destination point Y, which may be the cutter blade assembly 16, one must actuate a line switcher or “2 way valve” along the pipe.
Existing line switchers are designed to quickly divert flow from destination point Y to destination point Z and then back to destination point Y with minimal damage to the product being conveyed. Such devices contain moving parts that direct the flow one way or another, and therefore they often damage the product when they are used. It is a weakness of conventional line switchers that they can only provide an “either-or” switch. That is, when the product flows from source X, the prior art can only present the destination as either Y or Z, and not Y and Z.
According to the present technology of which the inventors are aware, there is no device that allows damage-free diversion of food product being conveyed from source X to either destination Y, or destination Z, or to both destinations Y and Z.